A US lawmaker has revealed that there are hundreds of Americans, who have links with ISIL militants and can return to the US with their American passports.

“I'm very concerned because we don't know every single person that has an American passport that has gone and trained and learned how to fight,” Mike Rogers, a Michigan Republican who heads the House Intelligence Committee, said on Sunday.

Rogers noted that these American citizens have at least once traveled, participated and trained with the terrorists and that US intelligence service is currently tracking them.

If these Americans have helped ISIL, they should be charged under laws, which prohibit US citizens from helping terrorists, he opined.

“ISIL would like to have a Western-style attack to continue this notion that they are the leading jihadist group in the world," Rogers said.

The head of the Senate Intelligence Committee says Obama has been “too cautious” in dealing with the ISIL terrorist group.

Also, in a New York Times op-ed published Friday, Sens. John McCain and Lindsey Graham dismissed Obama's limited airstrikes against the terrorist group in Iraq as "tactical and reactive half-measures."

The terrorist organization commands a vast stretch of territory from central Syria to the environs of Iraq's capital, Baghdad.